A Pain In The Back? Prove It

Boston Team Works On Monitor To Test Those Aches

Bad backs have long been a popular excuse among malingering workers. When someone claimed he suffered from pain in the back, it was always impossible to prove that he didn`t.

But the game may soon be up for these goldbricks.

A machine that tells whether a person is experiencing back pain is under development at a Boston laboratory. If tests are successful, doctors may, in a few years, be able to measure whether a worker who claims that his back is killing him is telling the truth or just trying to duck some work.

The computerized device, called a muscle fatigue monitor, measures changes in the electrical signals that activate muscles. Early research indicates that certain recognizable patterns occur when muscles become tired. In muscles of the lower back, researchers believe, this is correlated with pain.

``Our early studies indicate a correlation,`` said Allen Cudworth, director of research at the Liberty Mutual Research Laboratories in Hopkington, Mass. ``We wouldn`t want to hang our hat on those studies because they aren`t large enough. We need more institutions to do studies before we can be sure. But it looks promising.``

The machine, which has been under development for 18 months, may even be able to predict who is likely to develop a bad back. It is intended to spot potential problems and prevent them, Cudworth said, as well as to get workers with real back problems back on the job quicker after therapy.

The device receives electrical signals through electrodes attached to the lower back of a patient. ``This measurement tells you what is actually going on in the muscle so you don`t have to rely on what a person says,`` Cudworth noted.

``When somebody tells you how he feels, that can be very subjective. We`re trying to produce a tool that will give an objective measurement.``

It is clear that electrical signals from the back muscles of healthy people are significantly different from those received from people with back pain, Cudworth said. Still questionable is whether the researchers can gather enough data to say with certainty when an electrical pattern indicates the absence of pain.

Cudworth said he hopes the monitor can be also used to screen people as part of a regular physical examination to spot those whose back muscles become fatigued quickly, indicating a risk for back problems.

These people could be given exercise regimens to follow to strengthen their back muscles, he said, and later examinations with the muscle fatigue monitor could determine what effect the exercises were having. The exercise programs would be adjusted as muscle strength improves.

``There are several exercises recommended to strengthen back muscles, such as sit-ups, but there really aren`t many studies to support how effective they are,`` Cudworth said. ``No one has done good evaluations of these exercise programs. We are trying to do a good one.``

Back problems are a major health and economic factor in the United States, with an estimated 80 percent of adults suffering from some degree of back pain at some time in their lives. An estimate from the American Academy of Orthopedic Surgeons is that 31 million Americans will have back pain at any given time.